1. Field of the Invention
The present invention relates to novel diorganopolysiloxanes comprising a benzotriazole functional group.
2. Description of the Prior Art
It is known to this art to modify diorganopolysiloxanes, whether along the polymer chain and/or at the end of the polymer chain, with various organic functional groups, with a view towards imparting specific properties to such silicone polymers.
A convenient technique for introducing these organic functional groups is to carry out a hydrosilylation reaction between a diorganopolysiloxane bearing at least one SiH group and an ethylenically unsaturated organic compound in the presence of a catalytically effective amount of a platinum catalyst.
Exemplary of such prior art are:
(i) U.S. Pat. Nos. 2,970,150 and 4,160,775, describing the addition of allyl or methallyl alcohol to a silane or diorganopolysiloxane bearing at least one SiH group;
(ii) U.S. Pat. Nos. 3,767,690 and 4,503,208, describing diorganopolysiloxanes bearing moieties containing an acrylate or methacrylate functional group;
(iii) U.S. Pat. No. 4,640,967, describing diorganopolysiloxanes bearing an epoxy and/or acrylate or methacrylate group and compositions comprised thereof for coating optical fibers; and
(iv) Patent EP-A-0,088,842, describing diorganopolysiloxanes bearing benzophenone groups.
Also, U.S. Pat. Nos. 4,316,033 and 4,373,060 describe alkoxysilanes bearing a benzotriazole functional group F. But these patents relate to the cohydrolysis of these functional silanes with colloidal silica and an alkyltrialkoxysilane to produce a silicone resin, namely, a polymer essentially consisting of the recurring units Q(SiO.sub.2), T(CH.sub.3 SiO.sub.1.5) and less than 2 mol % of FSiO.sub.1.5 units. This silicone resin, when cured, is used as a coating for surfaces made of plastic.
Nonetheless, these patents do not suggest the preparation of linear or cyclic diorganopolysiloxanes comprising a benzotriazole functional group.